The present invention relates to a shadow-free lamp assembly for use in dental and other purposes wherein shadow produced owing to the presence of a light intercepting body within an illumination area is avoided to a great extent and the beam of the reflected light is diffused uniformly within said illumination area.
In prior art, a so-called shadow-free lamp used as the lighting equipment for dental or other medical treatment comprises a paraboloidal reflector made of heat resisting glass (generally called a cold mirror) and a linear light source such as a linear halogen lamp. Such paraboloidal reflector for the shadow-free lamp should be designed so that the reflector produces a specified irradiation pattern in order to illuminate a particular spot such as an affected part of the patient and that sufficient shadow-free degree and uniformity degree of illumination can be secured even if rays of light are partially intercepted by the entry of some opaque body, such as physician's hand, within this irradiation pattern. However, such prior art shadow-free lamp could not provide sufficient shade-free and uniformity degree of illumination.
Accordingly, an object of the present invention is to provide a shadow-free lamp assembly which can enhance the shadow-free degree and the uniformity degree of illumination which cannot be obtained satisfactorily by conventional shadow-free lamps.
According to this invention, a shadow-free lamp reflector is provided by continuously arranging numbers of plane mirror segments of a rectangular shape along the long span of the paraboloidal reflecting surface. Each of the plane mirror segment is so arranged to reflect the light of a linear light source disposed at a location forward from the paraboloidal reflecting surface so that beams of the reflected light from each mirror segment illuminate a predetermined illumination area.
One preferred embodiment of the invention will now be illustrated by way of example while referring the accompanying drawings.